Removable data storage medium, medical device and method for operating a removable data storage medium

ABSTRACT

A removable data storage medium including a serial interface; a non-volatile storage medium; a memory controller controlling data transmission between the serial interface and the non-volatile storage medium, a receiving unit; and a write protection unit; wherein the receiving unit is configured to receive a device identification feature from a medical device that can be connected to the removable data storage medium; and the write protection unit is configured to compare the device identification feature with a predetermined internal criterion, and, if the device identification feature complies with the predetermined internal criterion, permits read and write access from the medical device to the non-volatile storage medium and, if the device identification feature does not comply with the predetermined internal criterion, limits access of the medical device to the non-volatile storage medium to read access.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of PCT/EP2015/000009 filed onJan. 6, 2015, which is based upon and claims the benefit to DE 10 2014200 533.7 filed on Jan. 14, 2014, the entire contents of each of whichare incorporated herein by reference.

BACKGROUND

1. Field

The present application relates to a removable data storage mediumhaving a serial interface, a non-volatile storage medium and a memorycontroller controlling the data transmission between the serialinterface and the non-volatile storage medium. More particularly, thepresent application relates to a medical device, comprising a deviceidentification feature and a serial interface for exchanging data with aremovable data storage medium. The present application further relatesto a method for operating a removable data storage medium having aserial interface, a non-volatile storage medium and a memory controllercontrolling the data transmission between the serial interface and thenon-volatile storage medium. Finally, the present application relates toa medical system, comprising a removable data storage medium and amedical device.

2. Prior Art

Removable storage media, for example USB memory sticks, are generallyknown.

In a medical environment, information is exchanged between individualmedical devices, but also between medical devices and otherwise usedcomputers, with the help of removable data storage media.

However, conventional removable data storage media do not always reachthe desired requirements for quality, data transmission speed and datasecurity in a medical environment. The consequences are incomplete datatransmission or data loss.

Moreover, there is a risk that malware is transmitted from the freelyaccessible computer to the medical devices via a removable data storagemedium, which is used both on medical devices as well as on freelyaccessible computers.

SUMMARY

It is an object to provide a removable data storage medium, the datacommunication with medical devices of which is improved with respect todata security. It is also an object to provide a medical device, thedata communication with removable data storage media of which isimproved with respect to data security. Moreover, it is an object toprovide a method for operating a removable data storage medium, whichenables secure data communication between the removable data storagemedium and medical devices. Finally, it is an object to provide amedical system, in which data communication takes place with enhanceddata security.

Such objects are solved by a removable data storage medium having aserial interface, a non-volatile storage medium and a memory controllercontrolling the data transmission between the serial interface and thenon-volatile storage medium, wherein the removable data storage mediumis further developed in that a receiving unit and a write protectionunit, which can be provided in the memory controller, being present,wherein the receiving unit is configured to receive a deviceidentification feature from a medical device that can be connected tothe removable data storage medium, and the write protection unit isconfigured to compare the device identification feature with apredetermined internal criterion, and, if the device identificationfeature complies with this criterion, to permit read and write access tothe non-volatile storage medium and, if the device identificationfeature does not comply with the criterion, to limit access to thenon-volatile storage medium to read access.

The removable data storage medium can be a mass storage, thenon-volatile storage medium of which is a flash storage, for example anEEPROM.

The removable data storage medium can be configured in a case when it isnot in the position to determine a device identification feature totreat this case such that the device identification feature does notmeet the criterion.

With such removable data storage medium, a data export from a medicaldevice to any computer system is possible. However, a data import andexport is only possible between such medical devices, which wereauthenticated based on their device identification feature by theremoved data storage medium for this type of data access. In otherwords, this means that the device identification features of theconcerned medical devices must have respectively complied with thepredetermined internal criterion of the removable data storage mediumbefore they receive full access to the removable data storage medium.The removable data storage medium thus classifies the medical devicesbased on their device identification features as trustworthy and permitsan unhindered data exchange between the thusly qualified appliances.

It is thus possible that data is exported from a medical device to anycomputer system in order to render or further process them there.Conversely, data from this computer system, which was not identified asa qualified medical system, is not transmitted to medical devices. Theremovable data storage medium only gives the non-qualified computersystem read access and no read and write access to the non-volatilestorage medium. Thus, the non-qualified computer system is not able totransmit data to the medical devices, which increases the data securityin such an environment. Neither the data saved on the removable datastorage medium nor the data present on the medical device can beinfected with malware.

For example, a predetermined code saved in the medical device, a serialnumber, a certain hardware equipment, information regarding themanufacturer of the medical device, for example an open or encryptedmanufacturer identification number or a manufacturer code, a type orversion number of the device, of the hardware and/or software equipmentetc. can be used as the device identification feature.

It is possible to form the device identification feature based onindividual or several of the named data, if applicable based on aspecific determined combination of different data. In other words, thedevice identification feature can be made up of several characteristics.The device identification feature serves to identify the medical device.It is thereby less important to uniquely identify a medical device assuch than to assign it to a class of trustworthy medical devices,between which an unrestricted data exchange should be possible.

For this purpose, the device identification feature is compared with apredetermined criterion present on the removable data storage medium. Aunique comparison can be performed so that the removable data storagemedium only communicates for example with a certain device with fullaccess (read and write mode). However, the removable data storage mediumcan identify a group of medical devices based on the comparison with thepredetermined criterion, wherein each device in this group is grantedfull access. For example, devices as of a certain serial number, as of acertain year of manufacture or devices from a certain manufacturer caneach be granted full access, i.e. read and write access, to theremovable data storage medium.

According to one embodiment, the removable data storage medium can befurther developed in that the receiving unit is configured to receivethe device identification feature via a wireless data link. For example,the receiving unit can comprise an RFID transponder. According tofurther embodiments, the receiving unit can comprise a Bluetooth and/ora NFC (New Field Communication) transponder.

The identification of the medical device via a wireless data link isadvantageous because this process can take place before the data storagemedium is connected to the concerned medical device via the serialinterface. Thus, the subsequent connection establishment between theremovable data storage medium and the medical device does not result ina further delay. Moreover, it is possible that the removable datastorage medium outputs, for example, an optical or acoustic signal,which notifies the user that a data link with the concerned appliance ispossible with full access or in read mode only. The user is thus alreadyable to decide how to proceed before establishing the actual data link.

In a further embodiment, the removable data storage medium can beenhanced in that the receiving unit is configured to receive data via anoptical data link, such as a photodiode.

According to a further embodiment, the removable data storage medium canbe advantageously enhanced in that the receiving unit is mechanicallyencoded and configured to interact with a complementary mechanicallyencoded transmitting unit on the medical device that can be connected tothe removable data storage medium.

The used receiving unit, i.e. for example the photodiode or themechanically encoded receiving unit, can be provided in direct proximityof the serial interface on the removable storage unit. It is thuspossible that the receiving unit interacts with the correspondingtransmitting unit of the medical device at the moment when the removabledata storage medium is also connected to the serial interface of themedical device.

The requirements for authentication and subsequent data transmission canbe advantageously established with a handle, which simplifies thehandling of the removable data storage medium.

According to a further embodiment, the removable data storage medium canbe configured as a USB memory stick, wherein a USB port is provided asthe serial interface. Such a removable data storage medium can have ahousing, in which the non-volatile storage medium, the memorycontroller, the write protection unit and the receiving unit are allarranged together. Such a removable data storage medium is compact androbust and thus suitable for use in a medical environment.

An object is also solved by a medical device, comprising a deviceidentification feature and a serial interface for exchanging data with aremovable data storage medium, wherein the medical device is enhanced inthat it comprises a transmitting unit, which is configured to transmitthe device identification feature to the removable data storage medium.

The medical device is advantageously configured for secure datacommunication with a removable data storage medium according to one ormore of the named embodiments. The aspects mentioned with respect to theremovable data storage medium thus also apply analogously to the medicaldevice.

According to a further embodiment, the medical device can be enhanced inthat the transmitting unit is configured to send the deviceidentification feature to the removable data storage medium via awireless data link. The transmitting unit can comprise an RFID tag, inwhich the device identification feature is stored in the form of a codeidentifying the medical device.

In one embodiment, the medical device is configured so that thetransmitting unit comprises a light emitter, such as, an IRlight-emitting diode. It is also possible to advantageously furtherdevelop the medical device such that the transmitting unit ismechanically encoded and configured to interact with a mechanicallyencoded receiving unit that can be connected to the medical device.

The same or similar advantages as those already mentioned with respectto the removable data storage medium also apply in the same or a similarway to the medical device according to one or more of the namedembodiments. These are not repeated in order to prevent the item frombeing reintroduced.

An object according is also solved by a method for operating a removabledata storage medium having a serial interface, a non-volatile storagemedium and a memory controller controlling the data transmission betweenthe serial interface and the non-volatile storage medium, wherein themethod can be enhanced in that a write protection unit and a receivingunit are provided and the method comprises the following steps:

connecting the serial interface of the removable data storage mediumhaving a serial interface of a medical device,

receiving a device identification feature from the medical device on thereceiving unit,

comparing the device identification feature with a predeterminedinternal reference criterion, and

setting read and write access to the non-volatile storage medium of theremovable data storage medium if the device identification featurecomplies with the criterion and limit of access to the non-volatilestorage medium to read access if the device identification feature doesnot comply with the criterion.

For the method, it does not matter which of the two steps “connectingthe serial interface” and “receiving the device identification feature”is performed first. It is also possible that the two steps take placemore or less simultaneously. If the removable data storage medium is notable to identify a device identification feature, then it is treatedlike a case when the device identification feature does not comply withthe criterion.

The method can be advantageously further developed in that the deviceidentification feature is received via a wireless data link, wherein thedevice identification feature is received by an RFID transponder and/orby a receiving unit, such as a photodiode, configured for an opticaldata link.

According to a further embodiment, the method can be enhanced in thatthe device identification feature is received at a mechanically encodedreceiving unit by mechanical interaction with a complementarymechanically encoded transmitting unit.

The same or similar advantages as those already mentioned in terms ofthe removable data storage medium also apply to the method for operatinga removable data storage medium.

Finally, an object is solved by a medical system, comprising a removabledata storage medium according to one or more embodiments and a medicaldevice according to one or more of the named embodiments.

In the medical system, the data communication with the help of removabledata storage media is considerably securer than in conventional systems.However, the restrictions for data transmission are low since, forexample, data from the medical devices can be exported to furthercomputer systems in an unrestricted or unlimited manner. Otherwise, sameor similar advantages as those already mentioned in terms of theremovable data storage medium also apply to the medical system.

Further features will become apparent from the description ofembodiments together with the claims and the included drawings.Embodiments can fulfill individual features or a combination of severalfeatures.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described below without restricting the generalinventive idea using exemplary embodiments with reference to thedrawings, and for any details which are not explained further in thetext express reference is made to the drawings. They show in:

FIGS. 1 to 3 illustrate a medical system with a removable data storagemedium and a medical device, each in a schematic representation andaccording to different exemplary embodiments,

FIG. 4 illustrates a schematic flow diagram of a method for operating aremovable data storage medium, according to an exemplary embodiment,

FIG. 5a illustrates a schematically shown communication schema in amedical system, comprising a removable data storage medium according tothe prior art and

FIG. 5b illustrate a schematically drawn communication schema in amedical system, comprising a removable data storage medium according toone exemplary embodiment.

In the drawings, same or similar elements and/or parts are provided withthe same reference numbers in order to prevent the item from needing tobe reintroduced.

DETAILED DESCRIPTION

FIG. 1 shows in a schematic representation a medical system 2 a,comprising a removable data storage medium 4 and a medical device 6.

The removable data storage medium 4 comprises a serial interface 9 a,such as a USB port, which is provided within the USB plug 8. Moreover,the removable data storage medium 4 comprises a non-volatile storagemedium 10, for example a flash memory, like an EEPROM. A memorycontroller 12, which controls the data transmission between the serialinterface 9 a and the non-volatile storage medium 10, is located betweenthe non-volatile storage medium 10 and the serial interface 9 a presentwithin the USB plug 8. The non-volatile storage medium 10, the memorycontroller 12 and the serial interface 9 a are interconnected throughsuitable data lines. This is shown schematically in FIG. 1 by lines.

The USB plug 8, such as a standard USB plug, represents the physicalinterface of the removable data storage medium 4 to a host computer,such as a medical device 6. For the data communication with theremovable data storage medium 4, the medical device 6 comprises acorresponding USB socket 14.

The medical device 6 is, for example, a video management control unit,which is used in a medical environment, such as in an intensive careenvironment, such as for example an operating theater or room. Themedical device 6 can also be any other medical device, for example atherapeutic or diagnostic device, which serves to generate image data,which can be queried via an internal serial interface 9 b connected tothe USB socket 14. For this purpose, the medical device 6 comprises thefurther components necessary, which are not shown in FIG. 1. The aboveexplanations also apply to the following exemplary embodiments.

The removable data storage medium 4 also comprises further componentsnot shown in FIG. 1, which are only left out for reasons ofsimplification. For example, the removable data storage medium 4comprises an oscillator, a LED indicating the operating state and aprinted circuit board, which receives the non-volatile storage medium,the memory controller and the other named electronic components. Theseexplanations also apply to all exemplary embodiments.

The removable data storage medium 4 comprises a receiving unit 16, whichis configured to receive a device identification feature of the medicaldevice 6 that can be connected to the removable data storage medium 4.For this purpose, the receiving unit 16 is configured to receive datavia a wireless data link 19. According to the exemplary embodiment shownin FIG. 1, the receiving unit 16 is an RFID transponder 18. Thereceiving unit 16 of the removable data storage medium 4 communicateswith a transmitting unit 20 of the medical device 6 via the wirelessdata link 19. In the shown exemplary embodiment, the transmitting unit20 of the medical device 6 is an RFID tag 22.

The RFID tag 22 comprises a device identification feature in the form ofa code identifying the medical device 6. This can be stored in the RFIDtag 22. The code identifying the medical device 6 can be for example aserial number, a type designation, a manufacturer designation, amanufacturer identification number, a manufacturer code, a hardware orsoftware configuration, a version number, etc.

In that the removable data storage medium 4 reads the deviceidentification feature of the medical device 6 using the RFIDtransponder 18, the removable data storage medium 4 is enabled tocompare this device identification feature, for example a manufacturerdesignation or a serial number, with a predetermined internal criterion.For this purpose, the removable data storage medium 4 comprises a writeprotection unit 13.

The write protection unit 13 can be implemented both as hardware andsoftware. The write protection unit 13 can be implemented as part of thememory controller 12.

The write protection unit 13 determines whether or not the querieddevice identification feature of the medical device 6 complies with theinternal criterion of the removable data storage medium 4. In otherwords, the removable data storage medium 4 determines whether or not themedical device 6 is qualified. The removable data storage medium 4ensures full access (i.e. read and write access) to the non-volatilememory 10 for qualified medical devices 6, while non-qualifiedappliances 6 are only granted read access to the non-volatile storagemedium 10.

The internal criterion is, for example, a criterion to be clearly met.In other words, the data storage medium 4 is configured to onlycommunicate with medical devices 6 from a certain manufacturer or withmedical devices 6 of a certain series.

According to a further exemplary embodiment, the write protection unit13 defines the criterion such that a minimum requirement must be met inorder to ensure read and write access. For example, a minimum hardwareor software version, version number, appliance number, year ofmanufacture, etc. may need to be met.

It is also possible that an internal list of potential criteria that mayneed to be cumulatively met is present in the removable data storagemedium 4 so that the device identification feature also complies withthe predetermined internal criterion when one or more of the queriedcriteria, for example a manufacturer designation and/or a serial number,greater than a predetermined value and/or a predetermined minimum aremet. Even a minimum satisfied safety standard of the medical device 6can be used as the device identification feature.

If the medical device 6 complied with the predetermined internalcriterion of the removable data storage medium 4, then the writeprotection unit 13 grants the medical device 6 read and write access tothe non-volatile storage medium 10. In all other cases, i.e. when thedevice identification feature does not comply with the predeterminedinternal criterion or no device identification feature can beidentified, the write protection unit 13 exclusively ensures read accessto the non-volatile storage medium 10. This is, for example, the casewhen an arbitrary computer system is connected to the serial interface 9a of the removable data storage medium 4.

The described allocation of the access rights to the non-volatilestorage medium 10 of the removable data storage medium 4 prevents datafrom any computer system from making its way onto different medicaldevices via the removable data storage medium 4, which serves as atransport medium. Thus, the spread of malware on medical devices 6 canbe avoided.

FIG. 2 shows a further schematically drawn medical system 2 b accordingto a further exemplary embodiment. In contrast to the medical system 2 ashown in FIG. 1, the removable data storage medium 4 with its USB plug 8is plugged into the USB socket 14 of the medical device 6.

For transmitting data from the medical device 6 to the removable datastorage medium 4, the serial interface 9 a, thus the USB port of theremovable data storage medium 4, is connected to the correspondingserial interface 9 b of the medical device 6, for example thus the USBplug 8 is plugged into the USB socket 14 of the medical device 6. Theremovable data storage medium 4 subsequently receives an applicationidentification feature from the connected medical device 6 on itsreceiving unit 16.

In the exemplary embodiment shown in FIG. 2, the transmission of thedevice identification feature from the medical device 6 to the removabledata storage medium 4 takes place with the help of an optical data link.For this purpose, the removable data storage medium 4 comprises aphotodiode 24. It receives the signals of a light emitter, such as aninfrared light-emitting diode 26, which is integrated into the medicaldevice 6 as a transmitting unit 20.

After receiving the device identification feature, the write protectionunit 13 of the removable data storage medium 4 compares the receiveddevice identification feature with an internal criterion. Read/writeaccess to the non-volatile storage medium 10 is subsequently establishedif the device identification feature of the medical device 6 complieswith the criterion. If this is not the case, then the access to thenon-volatile storage medium 10 is restricted to read access only.

Further details regarding the functionality of the removable datastorage medium 4 and of the medical device 6 were already explained whenmaking reference to the exemplary embodiment shown in FIG. 1.

For transmitting the device identification feature, the infraredlight-emitting diode 26 and the photodiode 24 of the medical device 6and of the removable data storage medium 4, respectively, are arrangedopposite each other. This is applicable when the removable data storagemedium 4 is connected to the medical device 6 (as shown schematically inFIG. 2). The transmitting unit 20 and the receiving unit 16 of themedical device 6 of the removable data storage medium 4 can lie oppositeeach other when the USB plug 8 of the removable data storage medium 4 isplugged into the USB socket 14 of the medical device 6. According to afurther exemplary embodiment (not shown), the transmitting unit 20 andthe receiving unit 16 are directly integrated into a specially shapedUSB plug 6 and USB socket 14, respectively.

FIG. 3 shows a further medical system 2 c in a schematic representation.The removable data storage medium 4 already described in detail inconnection with FIGS. 1 and 2 and the medical device 6 are equipped witha transmitting and receiving unit 20, 16, respectively, in the shownexemplary embodiment, which is mechanically encoded.

The transmitting unit 20 and the receiving unit 16 are encodedcomplementary mechanically and interact similar to a key-and-lockprinciple. For example, the removable data storage medium 4 is providedwith a pin 28 of a certain length. It works together with an additionalpin 30, which is located in a medical device 6. If both pins 28, 30 havea suitable length, in other words if they add up to a predeterminedlength, then a position sensor 34 present within the removable datastorage medium 4 (not shown in greater detail in FIG. 3), for example amicro switch, is activated, the switch position of which specifies thatthe medical device 6 is a qualified medical device 6. If the lengths ofboth pins 28, 30 are not coordinated, then there is no release.

According to a further exemplary embodiment, the pin 28 present on theremovable data storage medium 4 is provided with a characteristic shapeon its tip facing the medical device 6. In interaction with acomplementary counter shape, which is located on the additional pin 30,which is connected to the medical device 6, the suitable length of bothpins 28, 30 is configured in that the position sensor 34 is reactivated.

For example, if the mechanically encoded shape of the pin 28 does notfit the counter shape of the additional pin 30, then it enters toodeeply or not deeply enough into the recess 32 present in the medicaldevice 6 and the position sensor 34 is not activated.

The pin 28 present on the removable data storage medium 4 forms amechanical receiving unit 16 to this effect, and the additional pin 30present on the medical device 6 also forms a mechanical transmittingunit 20 to this effect. Only if the pin 28 is located in the correctposition when the removable data storage medium 4 is plugged in is fullaccess (read and write access) to the non-volatile storage medium 10granted by the write protection unit 13 present in the memory controller12.

FIG. 4 shows a schematic flow chart of a method for operating aremovable data storage medium 4. The method starts in step S1. Theserial interface 9 a of the removable data storage medium 4 issubsequently connected to the serial interface 9 b of the medical device6 (step S2). The removable data storage medium 4 subsequently receivesan application identification feature from the connected medical device6 on the receiving unit 16 (step S3). The steps S2 and S3 do not need tobe performed in the sequence shown in FIG. 3. According to a furtherexemplary embodiment, it is also possible that the applicationidentification feature is received before the serial interfaces 9 a, 9 bof the removable data storage medium 4 and of the medical device 6 areinterconnected. This case is possible when the device identificationfeature is transmitted via a wireless data link 19.

The device identification feature is subsequently compared with apredetermined internal criterion (step S4). If this comparison issuccessful, then read and write access to the non-volatile storagemedium 10 of the removable data storage medium 4 is set up (step S5). Inall other cases, i.e. if the device identification feature does notcomply with the predetermined criterion or a device identificationfeature cannot be identified, access to the non-volatile storage medium10 is restricted to read access (step S6). The method finally ends instep S7.

FIG. 5a schematically shows the communication of a removable datastorage medium 4 according to the prior art with any computer system 36on one side and with a medical device in a medical system 2 on the otherside. The double arrow shown in FIG. 5a between the removable datastorage medium 4 and the computer system 36 indicates full access to theremovable data storage medium 4, i.e. read and write access to itsnon-volatile storage medium 10. The removable data storage medium 4 alsocommunicates with the medical device 6 with full access. As can be seenin FIG. 5a , malware from the computer system 36 can get into themedical device 6.

In contrast, as shown schematically in FIG. 5b , access from anycomputer system 36 to a removable data storage medium 4 according to anexemplary embodiment of the invention is restricted to read access. Thisis indicated by the arrow pointing from the removable data storagemedium 4 in the direction of the computer system 36. Data transmissionin the opposite direction, i.e. from the computer system 36 to theremovable data storage medium 4, is not possible. Only in communicationwith a qualified medical device 6, which is qualified based on itsdevice identification feature, which complies with the predeterminedinternal criterion of the removable data storage medium 4, full accessindicated by a double arrow (read and write access) is possible.

Thus, communication between respectively qualified medical devices 6 ispossible with the help of the removable data storage medium 4 withoutrestrictions. At the same time, the data security in this internalsystem compared to known solutions is considerably increased.

While there has been shown and described what is considered to bepreferred embodiments of the invention, it will, of course, beunderstood that various modifications and changes in form or detailcould readily be made without departing from the spirit of theinvention. It is therefore intended that the invention be not limited tothe exact forms described and illustrated, but should be constructed tocover all modifications that may fall within the scope of the appendedclaims.

REFERENCE LIST

-   2 a, 2 b, 2 c Medical system-   4 Removable data storage medium-   6 Medical device-   8 USB plug-   9 a, 9 b Serial interface-   10 Non-volatile storage medium-   12 Memory controller-   13 Write protection unit-   14 USB socket-   16 Receiving unit-   18 RFID transponder-   19 Wireless data link-   20 Transmitting unit-   22 RFID tag-   24 Photodiode-   26 Infrared light-emitting diode-   28 Pin-   30 Additional pin-   32 Recess-   34 Position sensor-   36 Computer system

What is claimed is:
 1. A removable data storage medium comprising: a serial interface; a non-volatile storage medium; a memory controller controlling data transmission between the serial interface and the non-volatile storage medium, a receiving unit; and a write protection unit; wherein the receiving unit is configured to receive a device identification feature from a medical device that can be connected to the removable data storage medium; and the write protection unit is configured to compare the device identification feature with a predetermined internal criterion, and, if the device identification feature complies with the predetermined internal criterion, permits read and write access from the medical device to the non-volatile storage medium and, if the device identification feature does not comply with the predetermined internal criterion, limits access of the medical device to the non-volatile storage medium to read access.
 2. The removable data storage medium according to claim 1, wherein the receiving unit is configured to receive the device identification feature via a wireless data link.
 3. The removable data storage medium according to claim 2, wherein the receiving unit comprises an RFID transponder.
 4. The removable data storage medium according to claim 2, wherein the receiving unit is configured to receive data via an optical data link.
 5. The removable data storage medium according to claim 4, wherein the receiving unit comprises a photodiode.
 6. The removable data storage medium according to claim 1, wherein the receiving unit is mechanically encoded and configured to interact with a complementary mechanically encoded transmitting unit on the medical device that can be connected to the removable data storage medium.
 7. The removable data storage medium according to claim 1, wherein the removable data storage medium is a USB memory stick, which comprises a USB port as the serial interface.
 8. The removable storage medium according to claim 7, wherein the non-volatile storage medium, the memory controller, the write protection unit and the receiving unit are arranged in a common housing.
 9. The removable storage medium, wherein the write protection unit are provided in the memory controller.
 10. A medical device comprising: a device identification feature; and a serial interface for exchanging data with the removable data storage medium according to claim 1, wherein the medical device comprises a transmitting unit configured to transmit the device identification feature to the removable data storage medium.
 11. The medical device according to claim 10, wherein the transmitting unit is configured to send the device identification feature to the removable data storage medium via a wireless data link.
 12. The medical device according to claim 11, wherein the transmitting unit comprises an RFID transponder, in which the device identification feature is stored in the form of a code identifying the medical device.
 13. The medical device according to claim 8, wherein the transmitting unit comprises a light emitter.
 14. The medical device according to claim 13, wherein the light emitter is an infrared light-emitting diode.
 15. The medical device according to claim 7, wherein the transmitting unit is mechanically encoded and configured to interact with a mechanically encoded receiving unit on the removable data storage medium that can be connected to the medical device.
 16. A method for operating a removable data storage medium having a serial interface, a non-volatile storage medium and a memory controller controlling data transmission between the serial interface and the non-volatile storage medium, wherein the removable storage medium further having a write protection unit and a receiving unit, the method comprising: connecting the serial interface of the removable data storage medium with a serial interface of a medical device; receiving a device identification feature from the medical device on the receiving unit; comparing the device identification feature with a predetermined internal criterion; and setting read and write access to the non-volatile storage medium of the removable data storage medium if the device identification feature complies with the criterion and restricting access to the non-volatile storage medium to read access if the device identification feature does not comply with the criterion.
 17. The method according to claim 16, wherein the device identification feature is received via a wireless data link.
 18. The method according to claim 17, wherein the device identification feature is received by an RFID transponder.
 19. The method according to claim 17, wherein the device identification feature is received by a photodiode configured for an optical data link.
 20. The method according to claim 16, wherein the device identification feature is received at a mechanically encoded receiving unit by mechanical interaction with a complementary mechanically encoded transmitting unit.
 21. A medical system comprising: a removable data storage medium comprising: a serial interface; a non-volatile storage medium; a memory controller controlling data transmission between the serial interface and the non-volatile storage medium, a receiving unit; and a write protection unit; wherein the receiving unit is configured to receive a device identification feature from a medical device that can be connected to the removable data storage medium; and the write protection unit is configured to compare the device identification feature with a predetermined internal criterion, and, if the device identification feature complies with the predetermined internal criterion, permits read and write access from the medical device to the non-volatile storage medium and, if the device identification feature does not comply with the predetermined internal criterion, limits access of the medical device to the non-volatile storage medium to read access; and at least one medical device comprising: a device identification feature; and a serial interface for exchanging data with the removable data storage medium, wherein the medical device comprises a transmitting unit configured to transmit the device identification feature to the removable data storage medium. 